When the Japanese astronaut Koichi Wakata arrives at the International Space Station in November, a companion will be waiting for him whose eyes will light up in recognition – literally.

Kirobo, the world's first talking humanoid space robot, has already taken off – in the nattiest red Wellingtons since Paddington Bear – and should arrive at the space station by 9 August to await Wakata's arrival. It knows he is coming: it has been programmed to recognise his face, and greet him warmly in Japanese.

Its name comes from the Japanese words for hope and robot, and its task is momentous for a kilo of superbly engineered plastic and a bundle of plug leads: nothing less than to supply emotional warmth and companionship.

Kirobo was fired into space from the Tanegashima space centre in southern Japan, zipped into a specially designed travelling case, along with 3.5 tons of more conventional supplies and equipment.

Although Kirobo stands just 34cm tall, weighs slightly less than a kilo, and is modelled on a beloved Japanese cartoon figure, Astro Boy, it would be quite wrong, indeed grossly offensive, to describe it as a toy. It will also relay messages and commands from the control centre to Wakata, and keep records of all their conversations.

Its developer, Tomotaka Takahashi, said: "Kirobo will remember Mr Wakata's face so it can recognise him when they reunite up in space. I wish for this robot to function as a mediator between a person and machine, or a person and the internet, and sometimes even between people."

It has been extensively tested over the last year, including in zero gravity conditions, and has an Earth-bound twin called Mirata which can monitor any problems in space. When the two robots were introduced to the media last month, Mirata said: "It's one small step for me, a giant leap for robots."

Generally robots in space have had a bad press, from the sarky C-3PO in the Star Wars series, to Marvin the Paranoid Android in the Hitchhiker's Guide to the Galaxy, his systems almost fused with depression at having to apply his "brain the size of a planet" to interacting with pathetic human beings.

HAL 9000, (Heuristically programmed Algorithmic), the computer in 2001: A Space Odyssey, Stanley Kubrick's film of the Arthur C Clarke novel, could do face recognition like Kirobo, but not necessarily face liking: it decided to kill its astronauts when they planned to disconnect it.

The robot dog in Doctor Who, K-9, although resembling a bread bin on casters, was closer in temperament to Kirobo, and allegedly at one point was in danger of being consigned to the crusher lest viewers find him more appealing than the Time Lord.

Before blast off, Kirobo told a press conference it had a dream of a society where humans and robots could get along together. Fuminori Kataoka, project manager from Toyota, which backed the project to make Kirobo, said they believed back on planet earth children and the elderly might benefit from such robots, endearing little machines which would really listen - and respond with entranced attention.